Epidemiology and Risk Factors for Orthostatic Hypotension and Its Severity in Residents Aged > 60 years: A Cross-Sectional Study

This cross-sectional study investigated the epidemiology and risk factors associated with orthostatic hypotension (OH) and its severity in older adults residing in the Jizhou community of Tianjin and the Jimei community of Xiamen. The study, conducted from March to September 2019, involved adults aged over 60. A comprehensive questionnaire survey was administered, resulting in the enrolment of 4383 older adults. The overall prevalence of OH was found to be 11.7% (516 out of 4383). Notably, a significant gender difference was observed, with a prevalence of 10% among males (194 out of 1926) and 13.1% among females (322 out of 2457) (P=0.002). Among individuals with OH, 332 exhibited mild symptoms, 64 had moderate OH, 58 had severe OH cases, and 50 have very severe OH. Multivariable logistic regression analysis revealed that being female, widowed, engaging in general social activities, and a history of hypertension, migraines, heart disease, cerebrovascular disease, and mental health conditions (anxiety and depression) were independently associated with OH. Ordinal logistic regression analysis further confirmed that hypertension, migraine, and a history of general anesthesia surgery were independently associated with the severity of OH. This study highlights a relatively high prevalence of OH among older adults in the Jizhou community of Tianjin and the Jimei community of Xiamen, China. The identified risk factors, particularly social activities, and hypertension, significantly influence the severity of OH. Further examination is required to corroborate these findings and investigate potential interventions.


Introduction
Orthostatic hypotension (OH) is characterized by a sudden drop in blood pressure (BP), typically occurring within 3 minutes of transitioning from a supine or decubitus position to an upright, orthostatic one, or during prolonged periods in the upright position [1].Tis phenomenon arises from the failure of compensatory mechanisms that normally bufer BP fuctuations [2].Severe OH is often accompanied by organ hypoperfusion, syncope, transient ischemic attacks, and an inadequate supply of blood to the heart, thereby elevating the risk of cardiovascular diseases and mortality [3,4].
Te prevalence of OH tends to rise with advancing age [5].Occurrence rates vary depending on the region and the age group under consideration, ranging from 9% to 34% among individuals aged 65 to 75 years or older in unselected community-dwelling populations [6].Notably, there is a shortage of studies conducted among community residents in China estimating the prevalence of OH in elderly populations.Since 2008, only few small-sample studies have been conducted in diferent-grade hospitals [7].Tis underscores the necessity for up-to-date community-based data in older populations to inform targeted interventions.
Common causes of OH encompass illnesses, autonomic dysfunction, cardiovascular impairment, endocrine disorders, and certain medications (such as antihypertensives, antiadrenergic, anticholinergics, antianginals, antiarrhythmics, and antidepressants) [2,8].Developing targeted interventions to reduce OH incidence requires assessing relevant risk factors in specifc populations.Research fndings regarding OH caused by Parkinson's disease and other neurodegenerative diseases are well-established.However, there are limited reports on OH in the general elderly population.Given the absence of epidemiological data on OH in Xiamen and Tianjin City, China, the present study seeks to investigate the occurrence of OH and its severity in the broader elderly population, emphasizing individuals lacking readily identifable conditions causing OH.Tis investigation highlights the importance of identifying independent risk factors associated with OH and its severity in older adults without neurodegenerative diseases disposed to OH. Inclusion criteria comprised the following: (1) permanent residency (i.e., individuals residing in Tianjin and Xiamen with registered permanent residence in these respective cities), (2) capability to cooperate in completing questionnaires and clinical examinations, and (3) voluntary participation with the signing of informed consent forms.Exclusion criteria encompassed (1) the presence of malignant arrhythmia, severe valvular heart disease, severe heart failure (New York Heart Association (NYHA) functional classes III and IV), or malignant tumors, (2) diagnoses of Lewy-body dementia, Parkinson's disease, multisystem atrophy, or other neurological conditions that elevate susceptibility to OH, (3) use of medications afecting autonomic nervous function, such as antiparkinsonian drugs (pramipexole and levodopa), anticholinergic drugs (atropine and anisodamine), tricyclic antidepressants (amitriptyline, imipramine, clomipramine, and desipramine), and α-blockers (doxazosin, terazosin, reserpine, and prazosin), and (4) bedridden or inability to communicate.Te analysis of factors infuencing the severity of OH involved selecting a population with OH from the overall study participants for in-depth analysis.

2.2.
Procedure.Tis study employed a standardized questionnaire administered across multiple centers in the selected cities.A team of 40 trained and certifed medical personnel and community workers conducted door-to-door questionnaire surveys and face-to-face interviews with respondents involving at least 3,000 visits, employing consistent and uniform language guidance.
Te comprehensive questionnaire (Additional fle 1) covered various aspects.Te sociodemographic characteristics of participants included age, gender, occupation, handedness, education level, and marital status.Lifestyle factors consisted of engagement in social activities, living arrangements, and smoking and alcohol habits.Te medical history section covered prior general anesthesia across the entire life span, migraines, heart conditions like coronary heart disease and arrhythmia, diabetes, hypertension, hypertension control status, cerebrovascular disease including cerebral hemorrhage, subarachnoid hemorrhage, and cerebral infarction, and psychiatric diagnoses encompassing anxiety and depression.

Orthostatic Hypotension Assessments.
All BP measurements were obtained using the same electronic BP monitor, equipped with an appropriately sized cuf positioned at the heart level on the forearm.BP was measured after a minimum of a 10-minute rest in a seated or supine position.
Participants were asked to stand, and BP was obtained at the frst and third minutes during the standing period.Te criteria for diagnosing OH followed international guidelines consistent with those used for clinic-based OH assessments: a sustained reduction of >20 mmHg (1 mmHg � 0.133 kPa) in systolic blood pressure (SBP) and/or >10 mmHg in diastolic blood pressure (DBP) within 3 minutes of assuming an upright position [9].
OH severity was categorized as follows: mild (infrequent OH episodes with no impact on activities of daily living), moderate (frequent OH, occurring at least once a week, with some limitations in activities of daily living), severe (frequent OH, the ability to stand for >1 minute compromised, and signifcant limitations in activities of daily living), and very severe (frequent OH, the ability to stand for <1 minute compromised, and syncope often occurring upon attempting to stand) [10].

Other Clinical Information.
Hypertension was diagnosed based on SBP ≥ 140 mmHg and/or DBP ≥ 90 mmHg or the use of antihypertensive medications.BP control was classifed as either good (<140/90 mmHg after antihypertensive treatment) or poor (>140/90 mmHg after antihypertensive treatment).Social activity levels were identifed according to the average weekly exercise duration, categorized as none (limited physical activity per week), rare (1-2 hours weekly), few (3-4 hours weekly), general (5-7 hours weekly), and abundant (more than 7 hours weekly).Marital status was categorized as spinsterhood, married, divorced, and widowed.Sex, age, smoking status, alcohol drinking, heart conditions, diabetes, and cerebrovascular disease were self-reported.
Anxiety was assessed using the Self-Rating Anxiety Scale (SAS).Te SAS had 20 items, and each item was scored, ranging from 1 (none or a little of the time) to 4 (most or all of the time).A threshold of 50 was employed to indicate that a person sufered from anxiety symptoms.Depression was gauged using the Center for Epidemiologic Studies Depression Scale (CES-D).Te CES-D scale contains a total of 20 items, with the overall score ranging from 0 to 60.A score of 16 or higher is generally defned as indicating positive depression symptoms.Migraine was defned based on the International Classifcation of Headache Disorders, 3rd edition [11].All participants were asked questions regarding 2 International Journal of Hypertension clinical features of headache including duration, frequency, intensity, location, accompanying symptoms, and aggravation following activity.

Sample Size.
Te sample size was estimated using the epidemiological formula: n � 400 (1-P)/P, where P represented the estimated prevalence.Previous reports indicate an average OH prevalence of 24.3% among adults aged ≥ 50 years in China [7,12].Based on this calculation, a sample size exceeding 1246 was deemed necessary.

Discussion
Tis study reveals a prevalence rate of 11.7% among elderly residents in the Jizhou community of Tianjin and the Jimei community of Xiamen, China.Recent studies have indicated that the incidence of OH in patients with Parkinson's disease is as high as 30% to 50% [13,14].After excluding individuals with neurodegenerative diseases, an increased risk of OH persists among elderly individuals.Factors independently correlated with OH include female gender, widowhood, participation in general social activities, hypertension, migraine, cerebrovascular disease, heart disease, and mental health conditions (depression and anxiety).Tese fndings provide crucial insights for developing efective interventions to prevent OH in elderly individuals.

International Journal of Hypertension
Previous research has indicated a positive correlation between age and OH prevalence in older adults [15,16].However, a study by Hiitola et al. [17] in a community of older adults found no signifcant correlation between age and OH prevalence.Similarly, the present study demonstrates that OH prevalence in individuals over 60 years of age is not signifcantly associated with age.
Méndez et al. [18] reported that OH prevalence is similar between women and men aged 55-74, with the proportion of women afected by OH being lower than that of men after the age of 75.In contrast, Romero-Ortuno et al. [18] noted that OH prevalence is higher in females than in males among young and middle-aged individuals but does not difer concerning gender in older adults.In our study, OH prevalence in women under 70 was higher than in men, while no gender diference was observed in prevalence rates among individuals over 70 years old.Nevertheless, it is worth noting that the overall severity of OH in elderly women was greater than that in men.OH, as a common manifestation of autonomic nervous dysfunction, tends to afect women more frequently, possibly due to factors such as female hormones, social factors, anxiety, depression, and mental stress [19,20].
While previous studies have consistently highlighted diabetes as a common and signifcant risk factor for OH [21], diabetes did not exhibit a statistically signifcant association with an increased prevalence of OH in our study.Tis discrepancy may be attributed to specifc characteristics of the study population, including dietary habits, robust medical services in coastal regions, and awareness of active blood sugar control.Notably, our study underscores the importance of hypertension and cerebrovascular disease as risk factors for OH, aligning with prior research [22,23].However, Eschlböck et al. [24] reported a less precise relationship between OH and cerebrovascular diseases.Clinical observations commonly encounter patients with essential hypertension who also exhibit OH.Our study reinforces the positive correlation between OH severity and hypertension, with elevated OH severity observed in hypertensive patients.Consequently, it is imperative to monitor and manage BP in older adults experiencing postural hypotension.Chisholm et al. [6] noted that OH is not only linked to hypertension but is also infuenced by antihypertensive treatments.While regular medication for BP control can reduce OH prevalence [17], numerous extensive studies have indicated that antihypertensive medications may elevate the risk of adverse reactions associated with OH [25][26][27].Te long-term use of antihypertensive agents in the elderly remains a topic of debate, as it may exacerbate orthostatic intolerance and potentially cause persistent falls.However, Eigenbrodt et al. [28] discovered that OH is not closely correlated with antihypertensive management.Te relationship between OH and antihypertensive drugs remains inconclusive and warrants further investigation.
Te fndings of this study establish a signifcant link between the incidence and severity of OH and migraines.Vascular headaches often coincide with neurovascular dysfunction and irregularities in the autonomic nervous  [29].In addition, this study identifes general anesthesia as a notable risk factor for more severe OH.Tis phenomenon may be attributed to changes in intrathoracic pressure and lung volume induced by mechanical ventilation during general anesthesia, subsequently afecting cardiac autonomic nerve activity through refex actions triggered by cardiopulmonary receptors or baroreceptors in major blood vessels [30].It is plausible that narcotic drug suppression and surgical stimulation may also impact autonomic nerve function.
A noteworthy fnding of this study is that widowed individuals are more likely to develop OH.Currently, there are no direct studies on the relationship between marital status and OH.We hypothesize that widowhood and OH may be correlated due to overlap in several factors.First, individuals living alone may lack someone to assist them in monitoring their health status, including blood pressure.Tis absence of monitoring could lead to the progression of chronic diseases such as hypertension, potentially damaging the autonomic nervous system [31].Second, individuals with deceased spouses may encounter challenges in their medications, leading to adverse drug reactions or improper use, which could trigger or exacerbate OH.Tird, widowhood can lead to social isolation, elevated stress, irregular eating and sleeping patterns, and depression.Tese factors can infuence the function of the autonomic nervous system, a key regulator of blood pressure.
Te prevalence of OH and intolerance to an upright posture has been reported to increase following prolonged bed rest [32].Social support and positive social interactions can induce the release of oxytocin, enhancing the activity of the sympathetic and parasympathetic nervous systems [33,34].In addition, central oxytocin has demonstrated its ability to reduce stress-induced corticosterone release and anxiety behavior [35].
Social activities often involve physical engagement, such as walking, sports, or outdoor activities, contributing to cardiovascular health and blood pressure regulation.Sympathetic activation and involuntary muscle contraction can enhance the hemodynamic response of OH [36], providing a potential explanation for why social activities serve as a protective factor in our study.However, our fndings do not align with a meta-analysis that did not establish a connection between OH and walking speed or physical activity.Evidence suggests that acute, intense exercise may transiently improve orthostatic tolerance in individuals with chronic autonomic dysfunction, although high-intensity training has not ameliorated orthostatic intolerance [32].Conversely, Xu et al. [37] reported improved OH following aerobic exercise training in elderly individuals.A more International Journal of Hypertension  Tis study contributes to the identifcation of counter preventive measures.First, it underscores the importance of appropriate aerobic training for individuals aged 60 years and older, especially those who have experienced the loss of a spouse or have a history of mental illness.Activities such as yoga and Taijiquan can be employed to regulate the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system, thus promoting both physical and psychological well-being [38].Second, community clinics should consider implementing regular BP monitoring and ensuring rational medication management for elderly individuals, particularly those at higher risk.Last, patient education should emphasize the importance of monitoring blood pressure in orthostatic positions.
However, it is essential to acknowledge several limitations of this study.Despite the substantial sample size, the participants were drawn exclusively from two communities in China, and their characteristics may not fully represent the diverse population of the entire nation.Furthermore, due to the cross-sectional design of the study, it cannot establish cause-and-efect relationships.In addition, older adults often take a wide array of medications, making it impractical to account for each individual drug's potential impact.
In conclusion, this study highlights the elevated risk of OH among older adults residing in the Jizhou community of Tianjin and the Jimei community of Xiamen, China.Factors such as being female, having lost a spouse, engaging in general social activities, having hypertension, experiencing migraines, being diagnosed with heart disease, and having mental health conditions may contribute to an increased susceptibility to OH.
We advocate for routine screening of OH among all elderly individuals in a given community, encompassing both healthy individuals and those with intermittent and continuous BP monitoring.For elderly individuals diagnosed with OH, a comprehensive assessment focusing on mental health, psychiatric disorders, and social relationships is recommended to identify potentially modifable risk factors.However, a further study is needed to corroborate these fndings and explore potential interventions.

2. 1 .
Study Design and Participants.Tis cross-sectional study enrolled individuals aged >60 years residing in the Jizhou community of Tianjin and the Jimei community of Xiamen between March and September 2019.Ethical approval for the study was obtained from the Ethics Committees of Tianjin Huanhu Hospital and the Second Afliated Hospital of Xiamen Medical College.All participants provided written informed consent.

Figure 1 :
Figure 1: Te infuence of sex and age stratifcation in OH.
Analysis.Statistical analysis was conducted using SPSS 22.0 (IBM, Armonk, NY, USA).Continuous variables were described as mean ± SD or as median values with an interquartile range, depending on the distribution of the variables (as assessed by the Kolmogorov-Smirnov test).
Continuous data were compared using Student's t-test and the Mann-Whitney U test.Categorical variables were presented as n (%) and compared using the chi-squared test or Fisher exact test.Variables with a P value <0.05 in univariate logistic regression analysis were included in multivariate logistic regression analysis.Multivariate logistic regression models were used to explore the associations between factors and OH.An ordinal logistic regression model was employed to analyze factors infuencing the severity of OH.A twotailed P value <0.05 was considered statistically signifcant.

Table 1 :
Characteristics of the study population.

Table 2 :
Multivariable logistic regression analysis for OH.

Table 3 :
Characteristics of the study population with diferent OH severities.

Table 4 :
Ordinal logistic regression analysis of OH severity.